Creating Genetically Modified Tomatoes with Particle Guns

Jim Crocker
30th March, 2024

Creating Genetically Modified Tomatoes with Particle Guns

Image Source: Natural Science News, 2024

Key Findings

  • Scientists developed a method to genetically modify tomato chloroplasts, aiming for better crop traits
  • The technique could lead to tomatoes with disease resistance, higher nutrition, or stress tolerance
  • The study overcame challenges to isolate cells with a mix of modified and normal chloroplasts
In the realm of plant biotechnology, the quest to enhance crop traits has led scientists to explore the genetic transformation of chloroplasts, the plant cell components responsible for photosynthesis. A recent study by researchers at the TERI-Deakin Nano-Biotechnology Centre has made significant strides in this area by establishing a protocol for chloroplast transformation in tomato cultivars[1]. This development could potentially lead to tomatoes with improved characteristics such as disease resistance, increased nutritional value, or better tolerance to environmental stress. The study focused on two tomato cultivars, Pusa Ruby and Yellow Currant, selected for their high potential to regenerate after genetic modification—a crucial step for successful transformation. Researchers also included a control, the Green Pineapple cultivar, which had been previously used in chloroplast transformation research. The process involved the integration of foreign DNA into the chloroplast genome, which is separate from the plant's nuclear DNA and is inherited maternally, reducing the risk of gene flow to wild relatives. Chloroplast transformation has been demonstrated in other plants, such as rapeseed[2] and soybean[3], showcasing its potential for crop improvement. In rapeseed, a specific protocol was developed for transforming chloroplasts using cotyledonary tissues[2], while in soybean, a method to rapidly establish homoplasmy—where all chloroplasts within a cell contain the transformed DNA—was achieved[3]. These foundational studies provided valuable insights into the process of plastid transformation and set the stage for the current work on tomatoes. In the tomato study, scientists used a synthetic gene operon within a chloroplast transformation vector (pRB94) designed to integrate into the chloroplast genome. This vector included a chimeric aadA selectable marker gene, which conferred resistance to antibiotics spectinomycin and streptomycin, allowing researchers to identify successfully transformed cells. The transformation was carried out by coating tiny particles with the pRB94 plasmid and shooting them into leaf explants—a technique known as particle bombardment. A major challenge encountered during the study was selecting positive explants from among those that appeared dead following the bombardment and culture in selection media. Despite this hurdle, the team managed to isolate plastid transformants in a heteroplasmic state, where a mixture of transformed and non-transformed chloroplasts coexist within the same cell. The study also identified key parameters that could streamline the chloroplast transformation process, potentially leading to the more efficient production of homoplasmic, transformed plants. The significance of such research is underscored by previous successes in modifying the plastid genome to produce beneficial plant compounds. For instance, the plastid genome of lettuce was modified to produce astaxanthin, a valuable antioxidant[4]. This achievement not only demonstrated that transplastomic plants could grow and reproduce normally but also that they could synthesize complex molecules like astaxanthin in substantial amounts. The research at the TERI-Deakin Nano-Biotechnology Centre builds upon these earlier studies by adapting and refining the techniques for use in tomato plants. The ability to transform chloroplasts in tomatoes opens up new possibilities for improving this globally important food crop. The study's findings could eventually lead to tomatoes with enhanced features that benefit both farmers and consumers. In conclusion, the development of a chloroplast transformation protocol for tomatoes represents a promising advancement in plant genetic engineering. By leveraging the power of chloroplasts to express new genes, researchers are paving the way for innovative solutions to agricultural challenges. As this technology matures, we may see a new generation of genetically engineered crops that are more nutritious, more resilient, and more sustainable.

BiotechGeneticsPlant Science

References

Main Study

1) Chloroplast transformation in new cultivars of tomato through particle bombardment.

Published 28th March, 2024

https://doi.org/10.1007/s13205-024-03954-3

Related Studies

2) Chloroplast transformation of rapeseed (Brassica napus) by particle bombardment of cotyledons.

https://doi.org/10.1007/s00299-010-0828-6

3) Plastid transformation in soybean.

https://doi.org/10.1007/978-1-62703-995-6_22

4) Construction of transplastomic lettuce (Lactuca sativa) dominantly producing astaxanthin fatty acid esters and detailed chemical analysis of generated carotenoids.

https://doi.org/10.1007/s11248-013-9750-3


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